应用水热运移数值模拟优化地下水源热泵系统抽灌井布局

合理布局抽水井和回灌井是地下水源热泵系统长期有效运行的关键因素。以郑州市郑东新区为例,利用HST3D软件建立水热运移数值模型,优化设计地下水源热泵系统抽灌水井布局,预测地下水源热泵系统长期运行后对含水层的水热影响。结果表明:介质比热容及渗透率分别对含水层温度及水位影响显著,是较敏感的参数。方案3(3个回灌井垂直天然流向分布且位于抽水井下游)为最佳布井方式。抽灌量900,1 200,1 500及2 000m3/d所对应的合理布井间距分别为50,65,70及75m。相应布井方案的水源热泵系统运行20a,对含水层温度场的影响仅限于200m×200m的范围,抽水井温度变化小于1℃。

Optimum Location of Pumping and Injection Wells of Groundwater Heat Exchange System Using Numerical Modeling of Water and Heat Transport

Rational location of pumping and injection wells is a key for long-term efficient operation of a groundwater heat exchange system.Numerical modeling of groundwater and heat transport in Zhengdong New District of Zhengzhou was established to optimally locate the pumping and injection wells of groundwater heat exchange system,and to forecast the influence of long term operation of groundwater heat exchange system on flow and heat in aquifers.It is concluded that specific heat capacity and permeability are sensitive parameter and their changes will significantly impact on heat and head in aquifers respectively.Scheme 3(three injection well vertical to natural flow direction and downwards the pumping well) is an optimized location of the wells.Rational distances between pumping and injection wells for the pumping/injection rates of 900,1 200,1 500 and 2 000 m3/d are 50,65,70 and 75 m respectively.The influence of the groundwater heat exchange system that wells are located as scheme 3 is limited to the range of 200 m×200 m after 20 year operation and the change of temperature in the pumping well is fewer than 1℃.